VSOCK: do not disconnect socket when peer has shutdown SEND only

[ Upstream commit dedc58e ]

The peer may be expecting a reply having sent a request and then done a
shutdown(SHUT_WR), so tearing down the whole socket at this point seems
wrong and breaks for me with a client which does a SHUT_WR.

Looking at other socket family's stream_recvmsg callbacks doing a shutdown
here does not seem to be the norm and removing it does not seem to have
had any adverse effects that I can see.

I'm using Stefan's RFC virtio transport patches, I'm unsure of the impact
on the vmci transport.

Signed-off-by: Ian Campbell <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Stefan Hajnoczi <[email protected]>
Cc: Claudio Imbrenda <[email protected]>
Cc: Andy King <[email protected]>
Cc: Dmitry Torokhov <[email protected]>
Cc: Jorgen Hansen <[email protected]>
Cc: Adit Ranadive <[email protected]>
Cc: [email protected]
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Ian Campbell

net/vmw_vsock/af_vsock.c

@@ -1796,27 +1796,8 @@ vsock_stream_recvmsg(struct kiocb *kiocb,
 	else if (sk->sk_shutdown & RCV_SHUTDOWN)
 		err = 0;
 
-	if (copied > 0) {
-		/* We only do these additional bookkeeping/notification steps
-		 * if we actually copied something out of the queue pair
-		 * instead of just peeking ahead.
-		 */
-
-		if (!(flags & MSG_PEEK)) {
-			/* If the other side has shutdown for sending and there
-			 * is nothing more to read, then modify the socket
-			 * state.
-			 */
-			if (vsk->peer_shutdown & SEND_SHUTDOWN) {
-				if (vsock_stream_has_data(vsk) <= 0) {
-					sk->sk_state = SS_UNCONNECTED;
-					sock_set_flag(sk, SOCK_DONE);
-					sk->sk_state_change(sk);
-				}
-			}
-		}
+	if (copied > 0)
 		err = copied;
-	}
 
 out_wait:
 	finish_wait(sk_sleep(sk), &wait);